Modern bathrooms often contain free-standing showers that are separate from the bathtub. Some showers have a molded plastic base that also serves as the floor. Other showers have a base upon which ceramic tile and grout are laid. The term “tile” is used herein to refer to any material (ceramic tile, stone, marble, synthetic materials, etc.) that are laid onto a bed of grout. A shower base for a tiled floor is commonly known as a shower receptor. A common shower receptor is a pan made of metal or other suitable impervious material that is attached to the floor over the drain. The pan is coated with hot tar for waterproofing and to provide cushioning to the pan to reduce the possibility of cracking when the shower is used. After the tar has dried for several days, the tile and grout are applied. This “hot mopping” process is relatively expensive because of the manpower required. It also creates a delay of several days.
A variety of alternate shower receptors have been disclosed. For example, Young, U.S. Pat. No. 5,845,347, issued Dec. 8, 1998, discloses a plastic shower receptor produced by forming a plastic base, spraying a waterproof membrane over the base, and then placing flexible backer sheets over the waterproof membrane. Davis, Jr., U.S. Pat. No. 6,003,169, issued Dec. 21, 1999, discloses a shower receptor produced by forming a wooden base, applying sloped wooden stringers and/or polystyrene foam, and then placing an acrylic top layer over the sloped surface. Gerloff, U.S. Pat. No. 6,571,406, issued Jun. 3, 2003, discloses a shower receptor produced by forming a plastic base having gutters and channels in its upper surface. The base also has knobs that mate with indentations in the bottom surface of a floor tile that is placed onto the base. Smale, U.S. Pat. Appln. No. US2004/0205890, published Oct. 21, 2004, discloses a shower receptor made of polyurethane structural foam with an upper surface that is sloped toward a centrally located drain.
These shower receptors suffer from several disadvantages. First, the upper surfaces of their floors provide limited adhesion to the grout. Second, the bed of grout applied to their floors (and the resulting tile surfaces) may not have the desired slope to the drain. Accordingly, there is a demand for a shower receptor that provides excellent adhesion to the grout and that enables the tile to be set with exactly the same slope as the floor of the shower receptor.